1. Field of the Invention
This invention relates generally to a so-called air gun and, more particularly, to a compressed air weapon having two pressure cylinders and a trigger actuated valve.
2. Description of the Background
Various configurations and styles of compressed air guns are known today. One example of such a compressed air weapon is shown in German patent publication DE-OS 1,553,929 that shows a compressed air weapon having a barrel, a first compression piston arranged within a relatively large, low-pressure cylinder, a second compression piston arranged within a smaller, high-pressure cylinder, a cocking lever, and a valve housing having a pressure release that is activated by a trigger. In this known air rifle, the piston rod of the low-pressure cylinder forms the high-pressure cylinder, so that both cylinders are arranged behind the barrel co-axial with the axis of the barrel. The pressure release is acted upon by the pressure of the high-pressure cylinder in the opening direction and is held by a trigger rod in the closed position. A tapered sealing element seals in a tapered seat of the valve housing, which is crossed horizontally by a passage between the high-pressure cylinder volume and the bore of the barrel. The dead volume of the high-pressure cylinder is relatively large and does not contribute much toward powering the shot, because the high pressure passage must traverse the entire high-pressure cylinder piston rod. The arrangement of the two cylinders behind the barrel also requires a large overall length for the gun, and the valve member is subject to high stress transversally to its axis and, therefore, undergoes a large amount of friction. Moreover, the sealing element wears out rapidly, and during its movement the cocking lever is not locked against a recoil, making overall operation dangerous.
Another compressed air gun is known from German patent publication DE-OS 2,330,535, and this rifle includes only a single compression stage, which exercises correspondingly high stresses on the component parts, when the overall projectile force is the same as a two-stage compression system. In that air rifle, the cylinder is arranged under the barrel, and the pressure release is opened against spring tension.
An air gun having a spring-loaded piston is described in German patent publication DE-OS 2,631,256. In this air gun, the cocking lever has a recoil catch with a swivelling catch element that engages in the thread teeth of a screw. When the spring is extended, the cocking lever, therefore, cannot accidentally overshoot to the front; rather, it must be pulled to its back stop. An air gun also having a recoil catch is described in German patent publication DE-OS 3,611,731.
Another compressed air gun of the two-piston variety described above is known from German patent publication DE-OS 2,263,271. In that air gun, the piston of the low-pressure cylinder also constitutes the high-pressure cylinder, with the high-pressure piston being anchored to the block. The pressure release is a seat valve, which is opened by a trigger rod system against the pressure in the high-pressure chamber and against the force of a locking spring. The compressed air gun described in Swiss patent CH-PS 458 127 is constructed in a similar manner.